RGB lights are available in many guises. Many offer a variable range of color and intensity settings. In most cases there are no dynamic effects apart from projection lamps used in discos, such as GOBO (Goes Before Optics or Graphical Optical BlackOut) or projector type devices. These devices may be based on mechanical turning wheels, slides, or even LCD and DLP (Digital Light Processing) type technologies for modulating the light. Dynamic effects also include flashing and color changing lights; in these cases the light effect is dynamic while the source is static.
Projected patterns are to be alternated in order to obtain a dynamic light pattern with turning wheels or slides. This makes the lighting device mechanically complex, with relatively large lighting device constructions. The use of LCD and DLP type technology is electrically complex and requires user dedicated knowledge to make use of all possible features.
The use of photochromic materials is known in the art. U.S. Pat. No. 5,228,767, for example, discloses a headlight lens manufactured from photochromic glass such that the headlight is not noticeable during daylight hours when subjected to ultraviolet light. At night, in the absence of ultraviolet light, the lens is transparent and emits the light from inside the headlight.